Study On The Dielectric Properties And Broadband Microwave Absorption Properties Of 1D MnO₂ Nanomaterials

With the rapid development of communication technology and radar technology,the prevention of electromagnetic leakage of electronic equipment and the realization of high-efficiency electromagnetic stealth of weapons and equipment have become the focus of research in absorbing materials.The current research directions of absorbing materials have focused on low density,strong absorption,wide bandwidth and chemical stability.MnO2 nanomaterials show a high dielectric constant and dielectric loss,and promote the enhancement of microwave attenuation.The dielectric properties of the material are closely related to the microscopic morphology,but the internal relationship between the dielectric properties of the MnO2 nanomaterials and its structure is not yet clear.Therefore,it is of great significance to study the electromagnetic response characteristics of different MnO2 nanostructures to adjust the absorbing performance.In this paper,hydrothermal method was used to synthesize MnO2 nanomaterials with nanorod and nanotube structures through different reaction conditions.Both nanorods and nanotubes have a single morphology and stable structure.Both MnO2 nanorods and nanotube materials are ?-phase,with[MnO6]octahedral lattice structure.For these two one-dimensional composite materials,the real part ?' and imaginary part ?" of the permittivity both increase with the increased loading.With the increase of the test frequency,the ?' of all samples gradually decrease,which shows the typical Debye relaxation behavior.Due to the accumulation of polarized charges,the ?"increases with increasing frequency.The larger specific surface area and more surface dipoles make nanotubes exhibit higher dielectric constant and dielectric loss than nanorods.Therefore,MnO2 nanotubes can achieve an effective absorbing performance of-10 dB at a low loading(30wt%)and a thin thickness(1 mm),and still exhibit effective absorbing capabilities when electromagnetic waves are incident at a large angle.The MnO2 nanorods can achieve an effective absorbing capacity of 3.44 GHz bandwidth at the thickness of 4.8 mm.After the design of the metamaterial structure,the MnO2 nanorods can achieve an effective absorbing bandwidth of 14.32 GHz.It can be seen that MnO2 nanomaterial is a potential high-performance absorbing material and will show great application value in many fields.